1. Field of the Invention
The present invention relates to telecommunication networks and, more particularly, to a method and system for reporting events to subscribers in telecommunication networks.
2. Background of the Art
Telecommunication networks use various signaling systems for establishing calls between subscribers. At times, however, the networks may detect certain states or events that would prevent the networks from establishing calls between subscribers. These events may include, for example, when a called directory number is out of service, network lines are busy or down, a switching node experiences a problem, etc. In such instances, the networks instead report the detected events to the subscribers by playing prerecorded audible messages.
Specifically, when a subscriber places a call to another subscriber in a network, a switching node local to the calling subscriber receives a call request from the calling subscriber's device. The switching node then sends a route request to a signaling node in the network to determine a route for the call. If the signaling node determines a route, the signaling node returns to the switching node the directory number of the next node in the network through which the call must be routed. Otherwise, if the signaling node detects that the call cannot be established or routed such as when the called subscriber's directory number is out of service, the signaling node returns an error code to the switching node. The switching node then notifies the subscriber that the requested call cannot be established by playing a prerecorded audible message corresponding to the error code.
Although audible messages may be sufficient for reporting events to subscribers who use plain ordinary telephone service (POTS) telephone sets, such messages are not universally recognizable by all subscriber devices. For example, consider a subscriber who uses a telecommunications device for the deaf (TDD) to place calls to other subscribers in the network. When the network plays an audible message to report an event, neither the subscriber nor the TDD device would be able to recognize the message. Similarly, an application running in a desktop computer for dialing into, for example, a local Internet Service Provider (ISP) system cannot recognize audible messages received from the network or present such messages in a form that is recognizable to a subscriber.
As yet another example, consider subscriber devices used in automotive telemetric or remote reading applications. In such applications, subscriber devices send and receive data from remote systems by automatically placing calls over the existing networks. However, since these subscriber devices cannot process the audible messages that are reported by the networks, they cannot provide the subscriber with informative information as to the cause of most communication failures. Furthermore, these subscriber devices cannot automatically take corrective actions in response to most communication failures. Corrective actions may include, for example, redialing a directory number when network lines are busy or dialing a different directory number when a previously dialed directory number is temporarily out of service. As the number of subscribers who use these and other devices that cannot process audible messages increases, the need for reporting network events in formats that subscriber devices can process grows accordingly.
Furthermore, even with respect to those subscribers who use audible devices such as, POTS telephone sets, to communicate over the existing networks, there is a need to provide audible messages in languages that subscribers can understand. For example, a Spanish speaking subscriber may wish to receive audible messages in Spanish, whereas a French speaking subscriber may wish to receive audible messages in French.